hulk inclusion category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/ID0C1D -------------------------------- With a fixed inflight limit, offline workloads are still throttled even when no online workloads are running. Moreover, excessive idle inflight capacity can allow sudden offline bursts to impact online workloads, causing latency fluctuations. Introduce dynamic inflight limit adjustment, with a range from 0.1% to 100× of the configured value. The adjustment rules are: 1) When online workloads are throttled, reclaim offline budget and try to increase the total inflight limit. 2) When only offline workloads are active, increase inflight as needed without restriction. 3) If neither of the above conditions has been met since the last increase, attempt to reduce inflight to avoid excessive idle budget. Signed-off-by: Baokun Li <libaokun1@huawei.com> --- block/blk-ioinf.c | 94 +++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 86 insertions(+), 8 deletions(-) diff --git a/block/blk-ioinf.c b/block/blk-ioinf.c index baa40bbebf28..ecc38d76ff1a 100644 --- a/block/blk-ioinf.c +++ b/block/blk-ioinf.c @@ -15,13 +15,21 @@ #include "blk-mq.h" #define IOINFG_WEIGHT_UNINIT (CGROUP_WEIGHT_MAX + 1) -#define IOINF_MIN_INFLIGHT 30 +#define IOINF_MIN_INFLIGHT 3 #define IOINFG_MIN_INFLIGHT 1 /* default wake-up time in jiffies for backgroup job, see ioinf_timer_fn() */ #define IOINF_TIMER_PERID (HZ / 2) /* Minimum wait queue count for offline cgroups. */ #define IOINFG_MIN_WQ_NR 8 +/* scale inflight from 1/1000 to 100 */ +enum { + MIN_SCALE = 1, /* one thousandth. */ + DFL_SCALE = 100, /* one tenth. */ + SCALE_GRAN = 1000, /* The control granularity is 1/1000. */ + MAX_SCALE = 100000, /* A hundredfold. */ +}; + /* io.inf.qos controls */ enum { INF_ENABLE, @@ -68,6 +76,9 @@ struct ioinf { struct ioinf_params params; u32 inflight; + u32 scale; + u32 old_scale; + u32 scale_step; /* default time for ioinf_timer_fn */ unsigned long inf_timer_perid; @@ -313,6 +324,9 @@ static bool ioinf_inflight_cb(struct ioinf_rq_qos_wait_data *data) } rqw->exhausted++; + /* wake up ioinf_timer_fn() immediately to adjust scale */ + if (inf->scale < MAX_SCALE) + timer_reduce(&inf->inf_timer, jiffies + 1); return false; } @@ -508,7 +522,9 @@ static int ioinf_stat_show(void *data, struct seq_file *m) spin_lock_irq(&inf->lock); - seq_printf(m, "inflight %u->%u\n", inf->params.inflight, inf->inflight); + seq_printf(m, "scale %u/%u inflight %u->%u\n", + inf->scale, SCALE_GRAN, + inf->params.inflight, inf->inflight); seq_printf(m, "online inflight %d/%u, sleepers: %d\n", atomic_read(&inf->online.inflight), @@ -544,6 +560,49 @@ static struct rq_qos_ops ioinf_rqos_ops = { #endif }; +static void __inflight_scale_up(struct ioinf *inf, u32 aim, bool force) +{ + u32 new_scale; + + inf->old_scale = inf->scale; + if (aim < inf->inflight || inf->scale >= MAX_SCALE) + return; + + new_scale = DIV_ROUND_UP(aim * SCALE_GRAN, inf->params.inflight); + if (new_scale <= inf->old_scale) { + if (!force) + return; + new_scale = inf->scale + inf->scale_step; + } + + inf->scale = new_scale; +} + +static void inflight_scale_up(struct ioinf *inf, u32 aim) +{ + __inflight_scale_up(inf, aim, false); +} + +static void inflight_force_scale_up(struct ioinf *inf, u32 aim) +{ + __inflight_scale_up(inf, aim, true); +} + +static void inflight_scale_down(struct ioinf *inf, u32 aim) +{ + u32 new_scale; + + inf->old_scale = inf->scale; + if (inf->inflight <= IOINF_MIN_INFLIGHT || inf->scale <= MIN_SCALE) + return; + + new_scale = DIV_ROUND_UP(aim * SCALE_GRAN, inf->params.inflight); + if (new_scale >= inf->old_scale) + return; + + inf->scale = new_scale; +} + u32 ioinf_calc_budget(struct ioinf_rq_wait *rqw) { u32 new_budget; @@ -600,9 +659,12 @@ static void ioinf_sample_lat(struct ioinf *inf) static void ioinf_update_inflight(struct ioinf *inf, u32 new_online, u32 new_offline) { - - if (inf->inflight < IOINF_MIN_INFLIGHT) + inf->scale = clamp(inf->scale, MIN_SCALE, MAX_SCALE); + inf->inflight = inf->params.inflight * inf->scale / SCALE_GRAN; + if (inf->inflight < IOINF_MIN_INFLIGHT) { inf->inflight = IOINF_MIN_INFLIGHT; + inf->scale = inf->inflight * SCALE_GRAN / inf->params.inflight; + } if (new_online < inf->inflight) new_offline = inf->inflight - new_online; @@ -627,13 +689,22 @@ static void ioinf_timer_fn(struct timer_list *timer) struct ioinf_rq_wait *online = &inf->online; struct ioinf_rq_wait *offline = &inf->offline; unsigned long flags; - u32 online_budget, offline_budget; + u32 online_budget, offline_budget, total_budget; ioinf_sample_lat(inf); spin_lock_irqsave(&inf->lock, flags); online_budget = ioinf_calc_budget(online); offline_budget = ioinf_calc_budget(offline); + total_budget = online_budget + offline_budget; + + if (online->exhausted) + inflight_force_scale_up(inf, total_budget); + else if (!online->issued && online_budget <= IOINFG_MIN_INFLIGHT) + inflight_scale_up(inf, total_budget); + else if (inf->old_scale < inf->scale) + inflight_scale_down(inf, total_budget); + ioinf_update_inflight(inf, online_budget, offline_budget); spin_unlock_irqrestore(&inf->lock, flags); @@ -642,12 +713,14 @@ static void ioinf_timer_fn(struct timer_list *timer) static u32 ioinf_default_inflight(struct ioinf *inf) { - u32 inflight = inf->params.inflight; + u32 inflight = inf->params.inflight * DFL_SCALE / SCALE_GRAN; if (inflight < IOINF_MIN_INFLIGHT) inflight = IOINF_MIN_INFLIGHT; + inf->scale = DIV_ROUND_UP(inflight * SCALE_GRAN, inf->params.inflight); + inf->old_scale = inf->scale; - return inflight; + return inf->params.inflight * inf->scale / SCALE_GRAN; } static inline int ioinf_rqw_init(struct ioinf_rq_wait *rqw) @@ -986,9 +1059,14 @@ static ssize_t ioinf_qos_write(struct kernfs_open_file *of, char *input, spin_lock_irq(&inf->lock); inf->params = params; - if (inf->inflight != params.inflight) + inf->old_scale = MAX_SCALE; + if (inf->inflight != params.inflight) { + inf->scale = SCALE_GRAN; + inf->scale_step = DIV_ROUND_UP(SCALE_GRAN, + inf->params.inflight); ioinf_update_inflight(inf, inf->online.hinflight, inf->offline.hinflight); + } spin_unlock_irq(&inf->lock); blk_mq_unquiesce_queue(disk->queue); -- 2.46.1